Asenapine

• Schizophrenia
• Bipolar Disorder
• Acute Mania
• Psychosis

Asenapine is an atypical antipsychotic medication used to treat schizophrenia and bipolar I disorder. This medication is administered sublingually, which provides rapid absorption and avoids first-pass metabolism, making it unique among antipsychotic medications.

Mechanism of Action

Asenapine is a tetracyclic compound with a complex receptor binding profile. Its therapeutic effects are thought to be mediated primarily through a combination of dopamine D2 and serotonin 5-HT2A receptor antagonism. Additionally, asenapine has high affinity for numerous other receptors, including 5-HT2C, 5-HT6, 5-HT7, dopamine D1, D3, D4, alpha-1 and alpha-2 adrenergic, and histamine H1 receptors. This broad receptor profile may contribute to its efficacy across different symptom domains and its metabolic side effect profile.

Available Formulations

Asenapine is available as sublingual tablets in 2.5 mg, 5 mg, and 10 mg strengths. The black cherry-flavored tablets are designed to dissolve under the tongue and should not be chewed or swallowed. A transdermal patch (Secuado) is also available in 3.8 mg/24hr and 7.6 mg/24hr strengths for once-daily application.

Medical Uses

Asenapine is FDA-approved for acute treatment of schizophrenia in adults, acute treatment of manic or mixed episodes associated with bipolar I disorder (monotherapy or adjunct to lithium or valproate) in adults, maintenance treatment of bipolar I disorder (monotherapy) in adults, and acute treatment of manic or mixed episodes associated with bipolar I disorder in pediatric patients aged 10-17. Clinical trials demonstrated efficacy in reducing psychotic symptoms and mood episodes.

Dosing Guidelines

For schizophrenia, the recommended starting and target dose is 5 mg twice daily, which may be increased to 10 mg twice daily after one week based on tolerability. For bipolar disorder, the recommended starting dose is 10 mg twice daily (monotherapy) or 5 mg twice daily (adjunctive therapy), which may be reduced to 5 mg twice daily if not tolerated. The sublingual tablet must be placed under the tongue and allowed to dissolve completely (usually within 10 seconds). Patients should not eat or drink for 10 minutes after administration to ensure adequate absorption.

Important Safety Information

Asenapine carries a boxed warning regarding increased mortality in elderly patients with dementia-related psychosis; it is not approved for this use. The medication can cause orthostatic hypotension, especially during initial dose titration; patients should be advised to change positions slowly. QT prolongation may occur; avoid use with other QT-prolonging medications. Metabolic effects including weight gain, hyperglycemia, and dyslipidemia may occur. Neuroleptic malignant syndrome and tardive dyskinesia are possible with any antipsychotic.

Drug Interactions

Asenapine is primarily metabolized by CYP1A2 and UGT1A4. Strong CYP1A2 inhibitors (fluvoxamine) increase asenapine exposure; dose reduction may be necessary. Coadministration with other CNS depressants may enhance sedation. Avoid use with other QT-prolonging medications. Caution is advised with antihypertensive medications due to additive hypotensive effects. Asenapine does not significantly affect the pharmacokinetics of lithium, valproate, or paroxetine.

Special Populations

There are limited data on use during pregnancy; use only if the potential benefit justifies the potential risk. Neonates exposed to antipsychotics during the third trimester may experience extrapyramidal symptoms. Asenapine is excreted in breast milk in rats; caution should be exercised in nursing mothers. Safety and efficacy have been established in pediatric patients aged 10-17 for bipolar mania. Elderly patients may require lower doses and careful monitoring. No dose adjustment is needed for mild to moderate hepatic or renal impairment; severe hepatic impairment is contraindicated.